Method of manufacturing highly-strainable iron and steel constructions



Patented Dec. 9, lllzd.

KARL DAEVES AND EZEUNO WEISSENBERG, F DUSSEQDOBF, GERMANY, AS'SIGNORS T0film EIEMi-THYSSEN 65 60., AKTIEN-GESELLSGEAF'E, OF MULHEIMl-RUHR, GEE-iasns.

Mnrnon or sinnusncronme No Brewing.

To all whom .it may concern:

Be it known that we, KARL Danvss and BRUNo "Wnrssnnnnao, citizens ofthev German Republic, and residing at Dusseldorf. Germany, have inventedcertain new and useful lmprovenientsin a Method of Manufacturingl-lighly-Strainable iron and Steel Constructions, of which the followingis. a specification.

It is known to ascertain the reliability or safety of iron and steelconstructions, particularly of pressure-reservoirs, by a testlug-load.The magnitude of the latter can, however, be a limited one only, becauseotherwise single parts of the construction are eventually strainedbeyond the yieldpoint and are liable to cold-deformation, and thereby,or by other reasons, the quality of the material is permanentlyinfluenced in a detrimental Way without the damages caused being afterall perceiveble. Thus, on the contrary to the purpose intended, the

testing-load would result in endangering certain parts of theconstruction. (louse quently. the testingdoad cannot be increased muchabove the actual Working-pressure to be employed later on in practice. 1

It is further known that such changes of material and inner strains, foriron and steel, can be completely overcome by a recrystallization. Thelatter is attained by a short annealing Within the limits of temperatureat which the iron or steel ,arevvith in the scope of solid solution.This tempo ahuc lies with pure iron abovc=-900 can tig'rade and dropswith increased carbon contents down to 738 centigradc.

The improved method, according to the present invention, based upon acombination of corresponding working processes, and it is distinguishedby the fact that the construction to be tested is, after its requiredconnections-particularly weldings are finished, exposed, first, to a tsting-load up to the limit of the actually desired factor of safety and,then, after said test to such an annealing thah a rte-crystallizationtakes place which removes the noxious result of Application filed April28, 1323. Serial Ho. 635,285.

HIGHLY-STRAINMLE IRON AND ETEEL CON- TBUGTIQNS.

any overload caused by the test in the material of the construction. l

The improved method is particularly ,adapted for testing the reliabilityor safety of Weldings, especially of Welded pressure reservoirs such as,for instance, used for steam-boilers and the like.

Thereby, strainless steamboilers can be manufactured, which arepreviously tested for pressures amounting to a multiple of the actualworking-pressure at which the steamboilei is used in practice.

Heretet'ore, such stean1-boilcrs were exposed to a hydraulic test only,or" which the pressure did not much exceed the actual working-pressure,according to the German s'teamboiler law, for instance, for higherpressures kgs. per cm. only. Besides, in many such cases, it has beenfiroved that just theoverload occurring with hydraulic tests seriouslyendangered the material of the steam-boilers.

likewise, a reliable manufacture of scamless reservoirs of high satiety;of single constructional parts for bridges and buildings. ofhighly-"trained parts of machinery such as pulleys, Wheels, gearings andthe like, is possible according to the improved method.

Vl'hat we claim, is t A. method of manufacturing highlystrainable" ironand steel constructions consisting in exposing said constructions.first, to a testing-load up to the limit of the actually desired factorof safety and, then, after said test to such an annealing that are-crystallization takes place which removes the noxious result of anyoverload caused by said test in the material of said construcfions,substantially as set forth.

In testimony whereof we have hereunto set our hands in the presence oftwo sub scribing witnesses.

K1 er. DAEVES. BRUNO WEISSENBERG.

Witnesses S. F. K. STEPHAN, D. Acetic FRANK.

